YSL Touche Eclat is fabulous. As with all makeup, experiment with it and come up with the perfect way for you. First off you should try applying it and blending straight away, if this is enough coverage for you, you're sorted! If not, apply it carefully (no streaks), wait a minute or two then just blend the edges, this gives industrial coverage. If you're going to be flash-photographed, use Touche Eclat sparingly and mix with another non-light-refelcting (i.e no titanium or zinc oxide) concealer so you don't get glaring panda eyes.
Remember Touche is classed as a highlighting concealer, don't put it on flaws that need to be shadowed rather than highlighted. The best example of this is when people apply Touche to the bags directly under the lashes, this just magnifies their existence! Under these bags (that look more like 'pouches' I suppose....I really want you to get what I mean here!) the skin comes in line with the eye socket and here is where the ashen blue-toned skin starts. Think of Touche as visual polyfilla (rather than physical - that isn't a good look) it's light reflecting qualities plump the undereye skin so that it looks less sunken (it 'brings it out' if you like) and evens the balance between your lower lash line 'pouches'. Not everyone has these pouches, and some are less prevalent, but if you do suffer from these, don't slap Touche all over them, it will only highlight them.
As for yellow colour correction under the eye, I have no idea why (some) companies are claiming it will do the trick. You may think it's better at concealing ashen undereye tones because before you have used a pink-toned foundation or concealer. Yellow will always work better than pink at concealing ashen tones, as pink has a tendency to go greyish when used in this way. So yellow is the lesser of two evils. If you study the colour wheel, however, you will see that orange will neutralize blue. Now because your undereye tone is not vivid blue, you will not need to use vivid orange, a peach colour (often used by Asian women with particularly sallow undereye skin) will suffice. MAC offer a peach colour corrector, which, used sparingly, works wonderfully either on its own or in conjunction with other concealers (Touche included - fab effects).
I rate Lily Lolo makeup, they have a 'Peep-O' yellow undereye concealer apparently for dark circles. I have found their blondie concealer does a better job of it! It works like a powder version of Touche as it contains the same light reflecting ingredients. Instead, I use their 'Peep-O' as a very effective colour corrector for high colour, as yellow gives a far more natural effect than traditional green.
A long one, I know, but hope this helps :green:
